Polysaccharides which contain mannose are frequently present in the cell walls of higher plants, in particular in leguminous plants, and are considered to be a carbohydrate store in the seeds.
In several plants, it has been shown that endo-α-mannanase activity is mainly detected in the endosperm of seeds undergoing germination (Bewley, Trends Plant Sci 2, 464–469, 1997).
In the coffee bean, galactomannans in particular are found. The latter represent approximately 24% of the dry weight of the bean (Bradbury and Halliday, J Agric Food Chem 38, 389–392, 1990). These polysaccharides consist of a linear chain of mannosyl residues which are linked to each other via β-1→4 type linkages and to which are attached α-galactosyl residue monomers. It is also known that the enzyme named endo-β-mannanase (E.C 3.2.1.78) is a hydrolase which degrades (1→4)-β-mannan polymers, thus facilitating the exit of the rootlet during germination and releasing small oligosaccharides which are then used as a source of energy for the growth of the young plant.
In industrial processes, during the treatment of coffee, the mannan molecules and their derivatives constitute a considerable portion of the insoluble sediments. In addition, the fraction of these molecules which dissolves during the first extraction (approximately 50%) is also very poorly soluble, and is therefore responsible for the majority of the secondary precipitations which occur during the subsequent steps. In patent EP 0676145A, therefore, it has been demonstrated that it is possible to hydrolyse coffee galactomannans using an immobilized mannanase extracted from Aspergillus niger. 
EP application No. 98203742.6, itself, proposes the use of fragments of coffee DNA encoding at least one endo-β-mannanase involved in the hydrolysis of polysaccharides consisting at least of simple or branched mannan molecules linked to each other via a β (1→4) linkage.
It has, however, appeared advantageous to isolate other enzymes and genes derived from the coffee bean.